Liquid and slurry explosives of controlled high sensitivity

ABSTRACT

Dense liquid or slurry explosive compositions, which can be pumped or poured and detonated in very slender columns have a liquid menstruum made sufficiently sensitive per se for cap detonation in diameters as small as one-half inch. They comprise a complete solution of an alkali or alkaline earth metal perchlorate, e.g. sodium perchlorate, combined preferably with a small amount of ammonium or sodium nitrate, organic liquid fuel, preferably ethylene glycol, and solid particulate aluminum as fuel, TNT, PETN or RDX also can be added. Basic sensitivity is provided by molecularly adjacent fuel with all oxidizer in solution.

Unite States Patent 1 91 1111 3,765,967

Funk et al. Oct. 16, 1973 [54] LIQUID AND SLURRY EXPLOSIVES OF 3,331,7177/ 1967 Cook et al. 149/42 X CO T O HIGH SENSITIVITY 3,379,587 4/1968Cook 3,390,029 6/1968 Preckel..... [75] Inventors: Albert G. Funk; BoydL. Hansen; 3,390,032 /1968 Albert Melvin A. Cook, all of Salt Lake3,395,056 7/1968 Bronstein.. City, Utah 3,453,158 7/1969 Clay 3,465,6759/1969 Bronstein [731 Asslgneei g fi Chemicals, Salt Lake CItY,3,485,686 12/1969 Jessop et a] 149/42 x 22 Filed; Man 23 1972 PrimaryExaminer-Stephen J. Lechert, Jr.

AttorneyCharles J. Merriam et al. [21] Appl. No.: 237,585

Related U.S. Application Data ABSTRACT [63] Continuation of Ser. No.876,576, Nov. 13, 1969. Dense liquid or slurry explosive compositions,which can be pumped or poured and detonated in very slen- [52] US. Cl149/21, 149/2, 149/38, der columns have a liquid menstruum madesuffil49/39, 149/41, 149/42, 149/43, 149/44, ciently sensitive per sefor cap detonation in diameters 149/46, 149/47, 149/60, 149/61, 149/57,as small as one-half inch. They comprise a complete 149/69, 149/76,149/83, l49/85 solution of an alkali or alkaline earth metal perchlo-[51] Int. Cl C06b l/04 rate, e.g. sodium perchlorate, combinedpreferably [58] Field of Search 149/2, 61, 21, 70, with a small amountof ammonium or sodium nitrate, l49/44, 76, 60, 83, 42, 85, 41, 38, 43,39, organic liquid fuel, preferably ethylene glycol, and 46, 47, 57, 69solid particulate aluminum as fuel, TNT, PETN or RDX also can be added.Basic sensitivity is provided [56] References Cited by molecularlyadjacent fuel with all oxidizer in solu- UNITED STATES PATENTS 3,249,4765/1966 Clay et al 149/41 X 24 Claims, No Drawings LIQUID AND SLURIRYEXPLOSIVES OF CONTROLLED l-llGlh'l SENSlTIVITY This is a continuation,of application Ser. No. 876,576, filed Nov. 13, 1969.

BACKGROUND AND PRIOR ART In recent years a number of slurry explosiveshave been developed which are satisfactory for many purposes. Generallyspeaking, such a slurry comprises an aqueous continuous phase, usually aconcentrated aqueous solution of ammonium nitrate, or of ammoniumnitrate combined with sodium or other alkali or alkaline earth metalnitrate, or analogous inorganic salt of high oxidation potential, inwhich particulate fuels and/or sensitizers are suspended. Usually, apart of the oxidizer is suspended, too. Chlorates and perchlorates havebeen suggested as oxidizer components, as in U.S. Pat. No. 3,282,753,but these seldom have been used. Oxidizers have been suspended in watersolutions (U.S. Reissue Pat. No. 25,695) and in solutions containingglycol and other organic solvents (U.S. Pat. No. 3,390,029, forexample). thickeners such as guar gum or analogous polysaccharides,starches and the like, are commonly used as thickeners or gellingagents, in minor proportions, in the oxidizer solutions per se as wellas in slurries, to increase viscosity of the liquid phase and/or to givethe whole sufficient body to prevent gravitational segregation ofsuspended particles. These suspended particles comprise fuels, such asaluminum particles, for example. Another purpose of thickening is togive the slurry sufficient body to prevent intrusion of ground waterinto the blasting composition when placed in a hole where ground wateris present.

While the slurry explosives and related materials mentioned above arehighly satisfactory for many blasting purposes, particularly wherecolumns or charges of large diameter are useful and where relativelyhigh insensitivity is acceptable, they are often quite unsuitable forother uses. One reason is that they are too insensitive for detonationin slender columns, i.e. in boreholes of small diameter. They cannot bedetonated, as a rule, with ordinary caps or with detonating cord.Frequently they are difficult and sometimes impossible to detonate atall, even with large and relatively expensive boosters. There is a realneed for a mobile fluid or pumpable composition, i.e. a liquid orslurry-type explosive, which is sensitive enough to be detonated insmall diameter mass or column, even at low temperatures, by means of anordinary blasting cap or by means of conventional PETN cored fuse suchas Primacord or analogous detonating fuse.

More specifically, a requirement has been expressed for an explosivewhich is cap-sensitive at temperatures as low as 40 C but which, at thesame time, is not so sensitive as to be set off by a 30.06 U.S. Armycalibre bullet when packaged in a plastic bag. Such specifications areextremely difficult to meet. Uses for such an explosive may includevarious formations in rock and other places where only small boreholes,fissures, or the like are available to receive the explosive charge. Fordemolition work, a safe but fluid or fluent explosive of goodsensitivity may be needed. Wherever the slurry must flow by gravity intothe place where it is to be used, or wherever it can be pumped intoplace in a relatively slender column, there may be need for a detonablecomposition having a critical cross-section that is very small, in anycase no larger than the borehole diameter and preferably considerablysmaller.

For a further example, a need exists for a flowable liquid or slurryexplosive that can be dispensed, e.g. somewhat like conventional toothpaste, from a squeeze bottle or container containing a I to k inch hole.The blasting agent, in some cases, must be usable at a temperature of 40C. It is desirable that it be sensitive enough so that it can bedetonated at such a temperature by use of a cap. These requirements arevery difficult to meet. Not all of the compositions of this inventionwill meet all these requirements, but some of them will and most of themwill meet most of the essential requirements. Obviously, the highsensitivity required for detonation in such a slender column may be soinconsistent in some cases with the quality of being safe on impact of arifle bullet that one requirement or the other must yield. Essentially,however, the required properties are quite well met by the presentinvention.

A number of attempts have been made in the past to make a cap-sensitiveslurry, i.e. one which can be used in fairly small boreholes like sticksof dynamite, that is in columns about one to two inches in diameter.Single sticks of most nitroglycerine base or gelatin dynamites usuallycan be detonated by an ordinary blasting cap. In U.S. Pat. No.3,153,606, a so-called slurry explosive which is said to be of this typeis described. Such an explosive, however, usually has to be very low incontent of water and other liquid. In fact, compositions of this typehas been referred to as stick" slurries. Some of these are not mobileslurries at all or, if they could be called slurries, they are soviscous that they do not flow readily. Fluid mobility is desired in manycases and usually is required for purposes of the present invention. Infact, compositions suitable for this invention should be capable offlowing by gravity and of being pumped mechanically through hoses,pipes, and other tubular conduits.

It has also been suggested in the past that water, the usual liquid intowhich the oxidizer is dissolved, might be extended by use of a watercompatible organic liquid having fuel valve. Thus, in U.S. Pat. Nos.3,190,777, 3,235,423, 3,379,587, and others, compositions containingwater plus ethylene glycol, formamide, dimethyl formamide, methylalcohol, and other organic liquids are described. However, the purposeof the liquid organic fluids in these cases is primarily to extend theliquid phase, a purpose somewhat different from the purpose served bythe organic liquids of the present invention. Here, the added liquidsmust be both of significant fuel value and have strong solvency for theoxidizers used in the present invention.

The prior art has described also the use of particulate self-explosivessuch as TNT and nitrocellulose (smokeless powder) as in U.S. Pat. No.2,930,685, 3,235,425 and 3,331,717. In these cases, the explosiveparticles are generally fairly large, and some are entirely unsuitablefor use in slender column explosive charges. The present inventioncontemplates the use of much more finely divided particles of a moresensitive selfexplosive type, such as finely divided RDX or PETN, as anadditional aspect.

A number of attempts have been made in the past also to produce slurrytype blasting agents of higher sensitivity to detonation merely by usingsubstantial quantities of heat producing metals, especially by usingvery finely divided aluminum metal. In particular, the

fine flaked particle grades or so-called paint grade aluminums, havingparticle sizes such that most will pass through a 325 U.S. sieve, areknown to have strong sensitizing properties. These fine flaked metalparticles have high surface areas and are particularly beneficial, evenin small proportions, for sensitizing aqueous slurries. Such metals canbe used as an auxiliary fuelsensitizer in the present invention.

However, even with paint grade aluminum, the sensitivity of typicalprior art slurries, based usually on ammonium nitrate, or AN plus sodiumnitrate, generally is not nearly sufficient for purposes of the presentinvention. Moreover, a mixture of water with such a finely dividedaluminum sometimes tends to be unstable because of the aluminum-waterreaction which can occur at ordinary temperatures. Such a reaction, ofcourse, can be inhibited to some degree as described in US. Pat. No.3,113,059, but there is a limitation on use of extremely active aluminumin mixtures which contain water.

It has now been found that the sensitivity of an explosive slurry isdependent, to some degree, not only on the temperature at which theslurry is detonated but also on the solubility at that particulartemperature of the inorganic oxidizer salts in the liquid. The saltsolution, of course, serves as the liquid body continuous phase of atypical slurry. The influence of temperature on sensitivity isillustrated by a typical explosive slurry composition which has acritical diameter at 25 C of 2 inches, but whose critical diameterincreases to at least 2.5 inches when the temperature is dropped to 5 C.It appears likely, at least in theory, that if a true solution actuallyexisted at the lower temperature, there should be little or nodifference in sensitivity as measured by the critical diameter over thissmall temperature range. In many and probably in most slurries of theprior art, however, there usually is a very substantial change incritical diameter over a small temperature range. This appears to bedue, at least in substantial part, to the fact that whereas a truesolution of oxidizer, usually AN, is present in the higher temperature,at a moderately lower temperature some of the oxidizer salt has beenprecipitated or fudge-d out of solution. With AN particularly, this canoccur with a relatively small temperature drop. The solubility ofammonium nitrate in water drops very rapidly with decreasingtemperature. This is true, in varying degrees, with most powerfuloxidizer salts. in those cases where there is actually a true solutionof oxidizer and fuel, which can be maintained over a working temperaturerange, with oxidizer and fuel being intimately in contact, i.e.substantially in molecular contact with each other in the liquidregardless of the temperature changes, the adverse influence oftemperature on the sensitivity and critical diameter of the compositioncan be either essentially eliminated or at least very significantlyreduced.

Hence, one aspect of the present invention is the discovery of theimportance of keeping the oxidizer salt in solution, and of ways ofdoing so, over the range of temperature that is most likely to beencountered in practical use. It appears, in fact, that the sensitivityof an oxidizer solution, other things being equal, can be substantiallyincreased and maintained at an acceptable level over a reasonabletemperature range according to the present invention by proper choice ofsolvent, even when relatively poor fuels or oxidizers are used. This canbe accomplished by choice of either solvent or solutes (oxidizer salt)and by making as certain as can be that both a good quantity of aneffective fuel and substantially all the oxidizer stay in solutiontogether, and hence in molecular contact, over the expected temperaturerange.

It is therefore an object of the present invention to obtain in a fluidliquid or slurry type explosive, as nearly as possible, the generalorder and range of sensitivities of conventional solid or molecular typeexplosives such a TNT, RDX, and the like. Fluid compositions or slurriesthus are prepared wherein at least substantial parts of essential fueland oxidizer ingredients remain in solution together. Therefore, thesecompositions are not substantially affected by ordinary temperaturechanges.

By obtaining and keeping essentially true solutions of oxidizers andfuels in liquid, even in water, the necessary molecular relationshipsbetween fuel and oxidizer are maintained. Oxidizers, of course, must beappropriately selected, as well as fuels. By establishing eutecticpoints for two or more salt-type oxidizers chosen from a select group,it is possible according to this invention to obtain an even bettersolubility range of oxidizer ingredients in fuel-solvent solution, i.e.over a wider temperature range, than is possible with a single salt. Atthe same time, it is possible to obtain the advantages of maximumintermolecular contact within the composition by having most orsubstantially all of the oxidizer and at least a substantial part of thefuel in actual solution together. By this means a liquid body isobtained which is detonable per se.

A further aspect of the present invention is the discovery that theamount of water required can be reduced to or near a practical minimum.Enough solvent is needed to maintain a true solution at the temperatureof use. Water may and often does enter into reaction with or in presenceof finely divided aluminum or other metal such as magnesium, silicon, orboron, as a vigorous component. This happens provided requisite reactiontemperature and other conditions can be reached and maintained. SeeCook, The Science of High Explosives, ACS Monograph No. 139 (1958), page304.

Another aspect of the invention is its facilitating use of slurries athigher than normal density. Where liquid or slurry explosives can beused, and where they can be detonated at high densities theperchlorates, as oxidizers, have special advantages. For use inmolecular-type sensitive slurries, as mentioned above, they havesuperior properties.

SUMMARY A liquid or slurry explosive containing in fully dissolved state20 to 60 percent by weight of alkali or alkaline earth metalperchlorate, or ammonium perchlorate, preferably a sodium or calciumperchlorate or a mixture of these two, 2 to 10 percent of sodiumnitrate, 0 to 25 percent of water, and 5 to 25 percent of an organicfuel, which may be diol such as ethylene glycol, or a low molecularweight monoalcohol such as methyl or ethyl alcohol and, optionally, asuspended particulate fuel, such as finely divided self-explosive, or afine paint grade aluminum in proportions up to l or 2 percent, has asensitivity much greater than is expected in normal slurries. It has adensity, even when aerated, of at least 1.0 g/cc. Such a slurry may befortified by addition of conventional fuels in small or greaterproportions when they do not desensitize the composition,

such as aluminum, with or without insoluble carbonaceous particles;and/or soluble carbonaceous materials such as carbohydrates, e. g.sucrose or other sugars, and the like, or even with finely dividedexplosive sensitizers, such as particles of PETN(pentaerythritoltetranitrate). Particular advantages are obtained byusing a small amount of thickener and a combination of two or morepowerful oxidizer salts, which may include various combinations ofsodium or other perchlorate, sodium nitrate, ammonium nitrate, and/orcalcium nitrate to establish eutectic solubility properties in organicsolvents and or water. Calcium perchlorate is especially useful withsome particular fuels, such as methyl or ethyl alcohol. Use of loweralcohols and similar water compatible fuels in liquid form makes itpossible to use relatively very little or no water. Particularly,organic liquid fuels and solvents of the group consisting of ethyleneglycol, formamide or dimethyl formamide, methyl alcohol, ethyl alcohol,isopropyl alcohol, and mixtures of two or more of these, and/or sucrose,are useful. They preferably are used in solution in glycol or water.Aldehydes, ketones, amines, amides, and alcohol-amines may be used, aslong as they are watersoluble or water-compatible and provided they stayin solution, at the temperature of use to a significant degree, when theinorganic oxidizer salt is wholly or at least largely in solution also.

DESCRIPTION OF PREFERRED EMBODIMENT Example 1 A basic explosive solutionwas prepared by combining 52 percent by weight of sodium perchlorate,18.5% water, 5.5% sodium nitrate, and 24% ethylene glycol. Thiscomposition had a rather high density of 1.58 g/cc. This is advantageouswhen it is desired to place as much weight as possible of the explosiveand hence maximum energy in a given volume. Of course, the density canbe readily reduced and the composition made more sensitive by aeratingit with air, or other gas in line, widely distributed bubbles. Thisparticular composition, which was a liquid free of suspended solids, wasnot cap-sensitive at this density but it was fully detonable per se. Ithad a critical diameter at 25 C of 2 inches, which critical valueincreased to 2 7% inches at 5 C. It was possible to initiate adetonation of the same liquid by slurrying into it substantialproportions of a particulate self-explosive. Sixty parts by weight ofthe above solution, for example, were combined with forty parts byweight of particulate pentaerythritoltetranitrate (PETN), using a smallamount of a guar gum, 0.2% by weight, based on the total, to thicken thesolution so that the suspended solid particles of PETN would not settleout by gravity. This slurry mixture had a density of 1.78 g/cc. It wascap-sensitive in relatively small masses and in an unconfined columndiameter of 0.5 inches (paper tube). It was initiated with a No. 6blasting cap at various temperatures ranging from 30 C down to as low as30 C.

EXAMPLE 2 Another example of a slurry made according to the foregoingprinciples, comprised 90 parts by weight of the solution described abovein Example 1, that is, of sodium perchlorate, water, sodium nitrate, andethylene glycol. To this were added 8 percent by weight of a finelydivided aluminum designated LSA 132 and 2 parts of a still fineraluminum designated VM 804'.

The resulting slurry had a viscous consistency, achieved by adding athickening guar gum in quantities of 0.2 percent, using 0.1 percent of across-linking agent, H The composition had a density of 1.43 g/cc. Thedensity indicates there was probably a significant amount of airentrained in the form of fine bubbles. The composition was cap-sensitivein a Xv-inch diameter. It was initiated with a No. 6 blasting cap, downto a temperature of 0 C. In a diameter of z-inch it was initiated with asimilar cap at -l5 C. It detonated at 30 C in a 1-inch diameter with a40 gram, 50/50 pentolite booster.

Comparison of detonation velocities is interesting. The liquid mixture,by itself, had a detonation velocity of 2,300 m/sec., whereas the samemixture with aluminum added had a detonation velocity of 5,300 m/sec.

A slurry made up of the liquid of Exampes 1 and 2 in proportions of 60percent, with 40% PETN suspended therein and unconfined, was notdetonated by 30.06 rifle bullet impact. However, the aluminum mixture ofExample 2 did detonate when fired by such a bullet. The solution itself,without PETN or aluminum, was found on different thermal analysis to bestable up to 300 C. It showed an exotherm when PETN was added at 170 Cand exploded spontaneously at 178 C. The aluminum mixture was stable upto 265 C.

Example 3 Another composition was prepared consisting of 31.2 percent byweight of sodium perchlorate, l 1.1% water, 3.3% sodium nitrate, and14.4% ethylene glycol, as the liquid menstruum, and 0.1% guar gumthickener, plus 40 percent of particulate PETN obtained from a source inSweden. The solution without the PETN was explosive per se. This slurry,including PETN, had a calculated energy, Q, of 1,085 cal/g and a densityof 1.78 g/cc. PETN as used here was made to a particle size ofapproximately percent between 35 and +100 mesh. Attempts to make thesame formulation but with a finer PETN, of which 40 percent would pass a325 mesh sieve failed, apparently because the mix became too viscous andbecame a semi-gel at --40 C. The solution per se required an initiatormore powerful than a No. 6 blasting cap to detonate it in a 3 inchesdiameter column at 30 C.

Under some conditions, it appears that other explosives than PETN can beused, such as RDX or TNT. It was found in experiments, however, thatfinely divided RDX was less satisfactory than PETN at very lowtemperatures. It is expected that TNT, which is less sensitive would beeven less satisfactory.

EXAMPLE 4 Another composition was made up of 22 percent by weight ofsodium perchlorate, 17% water, 3% sodium nitrate, 8% ethylene glycol,all in solution, to which were added 0.2% of guar gum thickener, and 50percent by weight of finely divided PETN obtained from U.S.manufacturer. This slurry failed to shoot at 20 C in -inch columns withboth N0. 6 and No. 8 caps. in a l-inch column it failed with a No. 6 capbut fired satisfactorily with a No. 8 cap. The explosion made asubstantial dent in a 15-inch steel plate. This slurry had a density of1.77 g/cc and was very viscous at 20 C.

EXAMPLE 5 Using 60 percent of the same liquid composition as that ofExample 1, which had an oxygen balance per se of l.3, with 40 percent byweight of finely ground PETN (about 40 percent of which passed through a325 mesh Tyler screen), the resulting composition was mobile enough toflow slowly, i.e. could be pushed out of a squeeze bottle, but it wasalmost too dry to call a slurry, at 20 C. At 40 C it set up solid. Itdetonated with a No. 6 cap in a 35-inch column. Using 50 percent of thesame liquid and 50 percent by weight of the same PETN, the compositionwas much too dry to be considered a slurry. A mixture of 65 percent ofthe solution and 35 percent fine PETN was somewhat more fluid than the60-40 mix but still quite putty-like in consistency. It had a density of1.81 g/cc. This PETN contained 40 percent fine enough to pass a 325 meshTyler screen. The 65-35 mix detonated in Vz-inch diameter at 25 C. Whenpercent of paint grade aluminum was added, the mixture was too dry toflow and would not detonate with a cap. This illustrates the point thatthe compositions with both the oxidizer and the fuel largely or entirelyin solution can be more sensitive than drier mixes. Ordinarily, thedrier slurries are easier to detonate than wet ones.

EXAMPLE 6 A composition was made up of the following ingredients,percentage by weight:

Sodium perchlorate 19% Water 15.0 Sodium nitrate 2.6 Ethylene glycol 3.4Boric acid 0.05 Guar gum 0.2 Fine aluminum 10.0 PETN fine ground 50.0

This was too dry at 20 C to be called a slurry. It had a density of 1.82g/cc at 20 C and detonated in a r-inch column, with a No. 6 blastingcap, making a dent in a %-inch thick steel plate. It detonated also at20 C in a %ll'lCl'l column, with a similar No. 6 blasting cap. The PETNused here wa a medium fine ground product from Trojan Powder Co. ofwhich 40 percent passed a 325 mesh sieve.

EXAMPLE 7 Another composition was preared consisting of 33.3 percent byweight of sodium perchlorate, 3.5 percent sodium nitrate, 11.8% water,15.4% ethylene glycol, 1% guar gum thickener, and 33 and 2 percentrespectively of the fine and ultrafine aluminums described in Example 2.This mix, with an oxygen balance of 33.4 percent, had a density of 1.65g/cc and a detonation velocity of 5,390 m/sec.

EXAMPLE 8 Another composition was prepared with a solution containing 47parts by weight of sodium perchlorate, 5 parts of sodium nitrate, b 24parts water and 21 parts ethylene glycol. To this solution was added 1part of a guar gum thickener and small quantities of gas producingagents to aerate the slurry and reduce its density. The properites ofthe initial solution and the solution after being thickened and gassedare compared below:

Solution with Thickener Solution Alone and Gassing Agents Density (g/cc)L54 1.25

Critical Diameter (inches) 3 (minimum) 0.75 Detonation Velocity (m/sec)less than 2500 4800 Minimum Booster 30 grams No. 6 Blasting CapPentolite While the foregoing examples deal largely with sodiumperchlorate and sodium nitrate based explosives, i.e. where sodiumperchlorate is the major oxidizer used in he solution, otherperchlorates and nitrates can be substituted in part or even in full.

Calcium nitrate, though less sensitive in most cases than theperchlorates, is a particularly desirable ingredient in liquidexplosives which contain methyl alcohol. Calcium nitrate has goodsolubility in water, in methyl alcohol, ethyl alcohol, and in ethyleneglycol, even at low temperatures. Alone, or in combination with sodiumperchlorate, it has a low eutectic solubility point. In proportions ashigh as to percent of the total solution, commercial grades of calciumnitrate, which contain 14 to 16 percent water of crystallization andnormally contain a few percent of ammonium nitrate, have better (i.e.lower) fudge points than more dilute solutions of ammonium nitratecombined with sodium nitrate. See U.S. Pat. No. 3,249,476. Data aregiven in Table l.

TAB LE I AN SN CN* Fudge pt. Density *CN, calcium nitrate from Norway,containing 5% by weight of ammonium nitrate (AN) and 16% water ofcrystallization.

Obviously, calcium nitrate has desirable properties where it is desiredto keep the oxidizer in solution (low fudge point) as required by thepresent invention.

Calcium perchlorate as oxidizer or as a part of it, and methyl or ethylalcohol, as the liquid fuel, or part of it, appear to have merit becausethey both are highly soluble in water and have good reactivity.

From the foregoing, a preferred explosive composition will be seen toinclude both fuel and oxidizer in the solution, and preferably all orsubstantially all of the oxidizer is in the dissolved state. Thiscomponent comprises from as little as 20 to about as much as 60 percentby weight of oxidizer, and preferably includes at least one perchlorateselected from the group which consists of ammonium perchlorate, alkalimetal perchlorates, and alkaline earth metal perchlorates. Theperchlorate is the major oxidizer component but it is combined togetherwith a small amount of at least one other powerful oxidizer salt,preferably a nitrate selected from the group which consists of ammonium,alkali metal and alkaline earth metal nitrates. The salts should beselected to give a low eutectic solubility or fudge pointtemperature-wise so that they will not salt out of the composition toany large degree at the temperature of use.

The liquid may comprise 0 to 25 percent of water and 5 to 30 percent offuel; usually ethylene glycol is preferred but it can sometimes bereplaced or supplemented by one of the simple alcohols. A combination ofabout to 20 percent of water and a little more glycol or other organicsolvent, say to 25 percent is particularly desirable to make theexplosive solution per se. The organic liquid chosen should have atleast reasonably good combustion value, 7,000 btu. per pound or greater.Diethylene glycol has a value of about 7,600, methyl alcohol about9,500, and ethyl alchol about 13,600 btu., but the former is usuallypreferred for this invention.

To maintain its integrity, in presence or absence of water, even when noinsolubles are added, this liquid preferably y is thickened at leastmoderately by incorporation of a small amount of a thickener. Guar gumin proportions of 0.10 to 1.0 percent by weight is particularlysuitable. Starches may be used in larger quantities. Cellulosic gums andtheir derivatives are required in some cases. Examples of such gums aremethyl cellulose and hydroxyethylcellulose. The gum or starch preferablyis cross-linked by use of a crosslinking agent such as borax or analkali metal dichromate. This not only guards against undue waterintrusion from extraneous sources; it helps to hold suspended fuel orself-explosive particles against segregation. It also enables the liquidphase to trap and hold tiny bubbles of air or other gas which are neededfor increasing sensitivity. Such air or other gas may be introduced bymixing or beating the thickened liquid per se or by stirring particulatesolids into the liquid menstruum. Particles of fuels and/orself-explosives, such as aluminum and/or particulate PETN, RDX, TNT, andthe like, may be added. The liquid mass per se is a potent explosive,and is substantially oxygen-balanced, without these particulate fuels orself-explosives. In this respect it is quite distinct from the prior artslurries.

When particulate non-explosive fuels are used, those preferred comprisealuminum, sulfur, and carbonaceous solids such as ground coal orgilsonite. Preferred self-explosives are PETN, RDX, Composition B, EDNA(ethylenediaminedinitrate), or TNT. These should be chosen and used inproportions suitable to impart the desired sensitivity and to hold theoxygen balance within reasonable limits, in any case between 50 and +10percent. For finely divided aluminum, proportions up to 45 percent ofthe total composition, by weight, may be used. Proportions of to 40percent are preferred when maximum power is needed. Part of thisaluminum may be paint grade fine flaked aluminum; proportions of l to 2contribute to sensitivity. Sensitive self-explosives such as PETN may beused in proportions up to 65 percent by weight of the total slurry.Obviously mixtures of PETN, RDX, Composition B, TNT, and aluminum, orany two or more of these may be used. Since the liquid phase per se isfairly well oxygen-balanced, the particulate materials should bring atleast part of their own oxygen (as with selfexplosives) or should bereactive with water (as is aluminum under favorable conditions whenwater is present), or solid oxidizer should be present in the particu-.late or suspended phase. This may be the principal oxidizer(perchlorate) partly precipitated from the liquid or added separately,or it may be a separate oxidizer salt such as AN, SN, calcium nitrate,etc., added separately. As already noted, use of a small amount of oneor more of these salts is often preferred because it lowers the fudgepoint.

The compositions of this invention are particularly versatile. They canbe tailor-made both to the desired sensitivity and the desired power byappropriate selection of components by type and proportions. This hasnot been true of the prior art slurries which, in general, are much lesssensitive and less subject to sensitivity control. The liquid componentsthat are high in dissolved sodium perchlorate or other perchlorate, andhigh also in ethylene glycol or other organic fuel molecularly adjacentto each other, are quite sensitive per se. By adding substantialproportions of finely ground selfexplosives of the more sensitive type,which are reasonably in oxygen balance per se, such as PETN, still morehighly sensitive products are obtained. These can propagate a detonationwave in a very slender column, e.g. a column as small as /&-inch or lessin diameter or mean cross-section.

Where such high sensitive explosives are not needed, the content ofself-explosive, such as PETN, may be reduced, or eliminated.Alternatively, this particular selfexplosive may be replaced fully or inpart by one or more of the other self-explosives named above and/or byaluminum powder.

In many cases, addition of a small amount of very finely dividedaluminum, especially the flaked paint grade, is desirable because of itshigh fuel or energy value. It contributes very substantially to highsensitivity, even in well balanced liquid compositions. It is desirable,also, for the mechanical handling properties it imparts to thecomposition. It helps to lubricate the flow of the composition throughconduits and orifices as when it is dispensed through valves, pumps,hoses and other flow devices.

Two further examples were made. The first contained 73.5% calciumperchlorate and 26.5% methyl alcohol. This solution per se had a densityof 1.54 g/cc and was detonated in a 0.75-inch diameter column with a9-gram Pentolite booster. The second contained 60% lithium perchlorateand 40% forrnamide. This solution per se had the density of 1.57 g/ccand was detonated in a l-inch diameter column with a 9-gram Pentolitebooster.

It will be obvious that the above and other modifications, which willsuggest themselves to those skilled in the art, can be made within thespirit and purpose of the invention.

What is claimed is:

l. A sensitive blasting composition comprising a substantiallyoxygen-balanced liquid mass which is detonable per se and which includes0 to 25 percent by weight water and 5 to 30 percent by weight of awatercompatible organic liquid having fuel value of 7,000 BritishThermal Units per pound or greater selected from the group consisting ofdiols; methyl, ethyl or propyl alcohols; aldehydes; ketones; amines;amides and alcohol-amines and mixtures of two or more of these andhaving completely dissolved therein an oxidizer salt, said saltcomprising at least a major proportion of a perchlorate selected fromthe group which consists of ammonium, alkali metal, and alkaline earthmetal perchlorates, in which liquid said perchlorate remains completelydissolved and hence in molecular contact with said water-compatibleorganic fuel at the temperature of preparation and also at thetemperature of use, said liquid mass containing tiny entrapped gasbubbles, said composition having a bulk density of at least 1.0 gramsper cubic centimeter.

2. Composition according to claim 1 which also contains a small amountof an inorganic nitrate oxidizing salt which is substantially dissolvedboth at manufacture and use in said liquid mass to lower itscrystallization or fudge point.

3. Composition according to claim 1 which also comprises a finelydivided solid fuel suspended in said liquid mass and a thickener forsaid liquid to substantially increase its viscosity and to stabilizesaid finely divided suspended fuel against segregation from said liquidmass.

4. Composition according to claim 3 in which the solid fuel comprisesfinely divided metallic aluminum up to 45 percent by weight of the totalcomposition.

5. Composition according to claim 3 in which the solid fuel comprises afinely divided self-explosive.

6. Composition according to claim 5 in which the self-explosive ispentaerythritol tetranitrate.

7. Composition according to cairn l which also comprises a finelydivided solid fuel suspended in and insoluble in said liquid mass inproportions up to 65 percent by weight of the total.

8. Composition according to claim 1 which comprises 20 to 60 percent byweight of sodium perchlorate, an alcohol, a thickener sufficient tostabilize suspended particles against segregation from said liquid mass,and enough solid suspended particulate fuel to keep overall oxygenbalance within limits of 50 to percent.

9. Composition according to claim 8 which has its density loweredsufficiently by incorporation of additional quantities of air bubbles toincrease its sensitivity.

l0. Composition according to claim 8 wherein the solid fuel is aself-explosive in proportions up to 65 percent by weight of the totalcomposition.

11. Composition according to claim 10 in which the self-explosive ispentaerythritol tetranitrate.

l2. Composition according to claim 1 in which the liquid phase comprises20 to 60 percent by weight of density lowered by an amount of about 0.1to 0.3 g/cc. by including a dispersed gas therein.

15. Composition according to claim 14 which includes a thickener for theliquid.

[6. Composition according to claim 1 wherein said oxidizing saltcomprises calcium perchlorate and the organic liquid comprises methanol.

17. Composition according to claim 1 which comprises formamide as anorganic liquid.

18. Composition according to claim 1 which comprises a major proportionof a perchlorate and a minor proportion of a nitrate as the oxidizingsalt, said composition containing sufficient widely dispersed gasentrapped therein to lower its density about 0.1 to 0.3 grams per cubiccentimeter.

l9. Composition according to claim I in which said oxidizing salt iscalcium perchlorate.

20. Composition according to claim 1 where said organic liquid fuel ismethanol.

21. A sensitive blasting composition comprising a substantiallyoxygen-balanced liquid mass which is detonable per se and which includes0 to 25 percent water and 5 to 30 percent of a water-compatible organicliquid having fuel value of 7,000 British Thermal Units per pound orgreater selected from the group consisting of diols; methyl, ethyl orpropyl alcohols; aldehydes; ketones; amines; amides and alcohol-aminesand mixtures of two or more of these and having dissolved therein aninorganic oxidizing salt, said salt comprising a nitrate selected fromthe group of alkali metal and al kaline earth metal nitrates, saidwater-compatible organic liquid having sufficient solvency such thatsaid nitrate remains completely in solution and hence in molecularcontact with said organlc liquid at the temperature of manufacture andalso at the temperature of use, said liquid mass containing numeroustiny gas bubbles dispersed therein.

22. Composition according to claim 21 in which said organic liquid ismethanol.

23. Composition according to claim 21 in which said inorganic oxidizersalt is calcium nitrate.

24. Composition according to claim 21 wherein the organic liquid fuel isethylene glycol.

@23 6 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTWN latent No.65,967 Dated October 16, 1973 lnventofls) Albert G; Funk; Boyd L.Hansen; Melvin A. Cook It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

[73] Assignee: delete Iresco" should be Ireco.

Column 5, line 12, "and or" should be -and/or-;

Column 5, line 57, "30" shouldv be -40-.

Column 6, line 17, Exampes" should be Examples-.

Column 7, line 41, 'wa should be -was-;

Column 7, line 46, "preared" should be -prepared; Column 7, line 58,delete "b before 24--;

Column 7, line 62, properites should be properties-.

Column 8, line 11, he" should be --the-.

Column 9, line 14, delete "y" before -is Claim .7, line 19, "caim 1"should be -claim l-.

Signed and sealed this 2nd day of April 197A.

(SEAL) Attest:

EDWARD I LFLETCHERJR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents 23% UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTEGN latentNo. 5,967 Dated 0ctober 16, 1973 Albert G. Funk; Boyd L. Hansen; MelvinA. Cook It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

[73] Assiqnee: delete Ir-esco should be Ireco-.

Column 5, line 12, "and or should be and/or-; Column 5, line 57, 30should. be 40.

Column 6, line 17, "Exampes" should be -Examples.

Column 7, line 41, "wa" should be -was;

Column 7, line 46, "preared" should be -prepared-; Column 7, line 58,delete "'b before 24-;

Column 7, line 62, properites" should be properties--.

Column 8, line ll, "he" should be -the.

Column 9, line 14, delete "y" before -is Claim .7, line 19, cairn 1"should be -claim l-.

Signed and sealed this 2nd day of April 19%..

' (SEAL) Attest:

EDWARD I '.FLETCI-IER,JR. C. MARSHALL DANN Attesting OfficerCommissioner of Patents

2. Composition according to claim 1 which also contains a small amountof an inorganic nitrate oxidizing salt which is substantially dissolvedboth at manufacture and use in said liquid mass to lower itscrystallization or fudge point.
 3. Composition according to claim 1which also comprises a finely divided solid fuel suspended in saidliquid mass and a thickener for said liquid to substantially increaseits viscosity and to stabilize said finely divided suspended fuelagainst segregation from said liquid mass.
 4. Composition according toclaim 3 in which the solid fuel comprises finely divided metallicaluminum up to 45 percent by weight of the total composition. 5.Composition according to claim 3 in which the solid fuel comprises afinely divided self-explosive.
 6. Composition according to claim 5 inwhich the self-explosive is pentaerythritol tetranitrate.
 7. Compositionaccording to claim 1 which also comprises a finely divided solid fuelsuspended in and insoluble in said liquid mass in proportions up to 65percent by weight of the total.
 8. Composition according to claim 1which comprises 20 to 60 percent by weight of sodium perchlorate, analcohol, a thickener sufficient to stabilize suspended particles againstsegregation from said liquid mass, and enough solid suspendedparticulate fuel to keep overall oxygen balance within limits of -50 to+10 percent.
 9. Composition according to claim 8 which has its densitylowered sufficiently by incorporation of additional quantities of airbubbles to increase its sensitivity.
 10. Composition according to claim8 wherein the solid fuel is a self-explosive in proportions up to 65percent by weight of the total composition.
 11. Composition according toclaim 10 in which the self-explosive is pentaerythritol tetranitrate.12. Composition according to claim 1 in which the liquid phase comprises20 to 60 percent by weight of sodium perchlorate, up to 10 percent ofsodium nitrate and a thickener.
 13. Composition according to claim 12 inwhich the thickener is a cross-linked gum.
 14. Composition according toclaim 1 which has its density lowered by an amount of about 0.1 to 0.3g/cc. by including a dispersed gas therein.
 15. Composition according toclaim 14 which includes a thickener for the liquid.
 16. Compositionaccording to claim 1 wherein said oxidizing salt comprises calciumperchlorate and the organic liquid comprises methanol.
 17. Compositionaccording to claim 1 which comprises formamide as an organic liquid. 18.Composition according to claim 1 which comprises a major proportion of aperchlorate and a minor proportion of a nitrate as the oxidizing salt,said composition containing sufficient widely dispersed gas entrappedtherein to lower its density about 0.1 to 0.3 grams per cubiccentimeter.
 19. Composition according to claim 1 in which said oxidizingsalt is calcium perchlorate.
 20. Composition according to claim 1 wheresaid organic liquid fuel is methanol.
 21. A sensitive blastingcomposition comprising a substantially oxygen-balanced liquid mass whichis detonable per se and which includes 0 to 25 percent water and 5 to 30percent of a water-compatible organic liquid having fuel value of 7,000British Thermal Units per pound or greater selected from the groupconsisting of diols; methyl, ethyl or propyl alcohols; aldehydes;ketones; amines; amides and alcohol-amines and mixtures of two or moreof these and having dissolved therein an inorganic oxidizing salt, saidsalt comprising a nitrate selected from the group of alkali metal andalkaline earth metal nitrates, said water-compatible organic liquidhaving sufficient solvency such that said nitrate remains completely insolution and hence in molecular contact with said organIc liquid at thetemperature of manufacture and also at the temperature of use, saidliquid mass containing numerous tiny gas bubbles dispersed therein. 22.Composition according to claim 21 in which said organic liquid ismethanol.
 23. Composition according to claim 21 in which said inorganicoxidizer salt is calcium nitrate.
 24. Composition according to claim 21wherein the organic liquid fuel is ethylene glycol.